Aerodynamic forces on the roofs of low-, mid- and high-rise buildings subject to transient winds

Research output: Contribution to journalArticle

Colleges, School and Institutes

External organisations

  • School of Civil and Environmental Engineering, Rensselaer Polytechnic Institute
  • Rensselaer Polytechnic Institute

Abstract

Transient winds, such as thunderstorm downbursts, are the cause of design-load wind speeds in many countries. An understanding of the loading experienced by buildings during a downburst is therefore important to allow well designed and engineered buildings to be constructed. In contrast to boundary layer winds, the maximum wind speed in thunderstorm downbursts occurs as low as z<inf>m</inf>=30m above the ground, within the range of heights of man-made structures, suggesting that the wind loading will be dependent on the building eaves height relative to z<inf>m</inf>. In a novel set of experiments, the University of Birmingham Transient Wind Simulator (a 1m diameter impinging jet with aperture control) has been used to simulate a downburst striking buildings of different heights, ranging from below to above z<inf>m</inf>. Two forms of building have been used - a square-plan, flat-roofed structure, and a rectangular, portal-frame - at three angles (0°, 45° and 90°) relative to the radial wind direction. Pressure coefficients have been calculated (using eaves height velocity) over the roofs of these buildings, and are shown to be of greatest magnitude when the roof is above the region of maximum outflow velocity, with the exception of windward edges perpendicular to the flow, when they are generally greatest for the lowest building heights.

Details

Original languageEnglish
Pages (from-to)42-49
Number of pages8
JournalJournal of Wind Engineering and Industrial Aerodynamics
Volume143
Early online date28 May 2015
Publication statusPublished - Aug 2015

Keywords

  • Downbursts, Structures, Thunderstorms, Transient winds, Wind loading